Studies of copper valence states with CuL3x-ray-absorption spectroscopy

Abstract

We have used x-ray-absorption spectroscopy to study a series of compounds in which Cu assumes a formal valence between 0 and 3. We find that the shape, the threshold energy, and the intensity of the Cu L3 absorption edge is strongly inAuenced by the chemical state of the Cu atoms. We use the Cu 2p x-ray-absorption spectra of a large number of Cu compounds, including sulfides, oxides, LaSr-Cu-0 compounds, a phthalocyanine complex, and various minerals to show that the presence of a strong 2p-3d excitonic transition is a fingerprint of the Cu(d } contribution to the ground state. A simple ionic picture is generally inadequate to describe these compounds.

Polarized x-ray absorption spectroscopy study of the symmetry of unoccupied electronic states near the Fermi level in the system

“…The observed difference in the weightage of the Cu 3d z 2 orbitals is not due to the non-proportionality of the absorption coefficient to the FY signal. The well pronounced structure beyond the main excitonic line is, as predicted by Grioni et al [37] and Mei and Stollhoff [38], due to strong hybridization of Cu 3d with Cu 4s, 4p states and their weight may be as much as 20% of the total number of Cu 3d out-of-plane orbitals.…”

The role of Cu on the reduction behavior and surface properties of Fe-based Fischer–Tropsch catalysts

“…3d and e) at 931.3 eV 43,44 and a small contribution in the pre-edge region of the O K-edge spectra at 530.1 eV. 41 In addition, a contribution was visible in the Cu L 3 -edge at 933.7 eV, indicating a minor presence of Cu(I) species.…”

Doping dependence of the electronic structure ofBa1−xKxBiOKobayashi1, Mizokawa2, Ino3 et al. 1999Phys. Rev. BSelf Cite162100View full textAdd to dashboardCite

“…Photon energies were calibrated using the Cu 2p 3/2 edge of Cu metal at 932.5 eV [22] and the O 1s edge of LaCoO 3 at 529.3 eV [23]. O 1s XAS spectra were taken by the total electron-yield method with photoelectrons.…”